The present invention is directed to a trimmer for cutting hedges and similar plants. More particularly, the present invention is directed to a hedge trimmer with a rotating substantially circular blade mounted in a substantially circular housing.
Trimmers for cutting hedges, bushes and other ornamental plants and shrubs are in wide use today. The most popular version of the hedge trimmer today uses an elongated reciprocating cutting element driven by a motor. This arrangement tends to be somewhat unwieldy and dangerous.
Additionally, there has been some effort to produce a hedge trimmer having a substantially circular housing. For example, see U.S. Pat. No. 3,050,854xe2x80x94Becker et al. which discloses a hedge trimmer which utilizes a rotating elongated blade within a circular housing. More recently, U.S. Pat. No. 4,641,431xe2x80x94Leming et al. discloses a hedge trimmer which utilizes a metal wire whip which is rotated at very high speed within a circular housing for trimming hedges.
An advantage of the present invention is that it provides a lighter-weight apparatus.
Another advantage of the present invention is that it operates more quietly than a reciprocating hedge trimmer.
Another advantage of the present invention is that it provides increased safety by preventing or making it more difficult for a person to get a body part, such as a finger or hand, in contact with the cutting blade.
Another advantage of the present invention is that it provides a more balanced hedge trimmer.
Another advantage of the present invention is that it provides a smoothly operating substantially circular blade.
Another advantage of the present invention is that by providing a substantially circular blade, the cutting elements may be moved at a faster rate than if the cutting elements were on a reciprocating blade.
Another advantage of the present invention is that it is adapted to cut when moved in the natural direction of the tool being swung by an arm of a user.
Another advantage of the present invention is that it provides a relatively compact hedge trimmer.
Another advantage of the present invention is that it provides a release mechanism to prevent damage in the event that the blade is stalled when the motor is operating.
Another advantage of the present invention is that it provides airflow out of the housing to remove debris.
Another advantage of the present invention is that the blade is substantially completely enclosed within the housing.
Another advantage of the present invention is that it provides simple tool-less removal of the blade for sharpening, replacement or the like.
Another advantage of the present invention is that it provides a safe and secure housing latching means which still allows the housing to be easily opened.
Briefly and basically, in accordance with the present invention, a lightweight, quiet and safe apparatus for trimming hedge and the like is provided. The use of the term hedge throughout is meant to include all types of hedge, bushes and other ornamental plants and shrubs that usually produce new growth which may be trimmed by what is commonly referred to as a hedge trimmer.
In accordance with the present invention, a substantially circular housing is provided with a handle projecting from the housing. A substantially planar circular blade having a plurality of cutting elements thereon is mounted within the substantially circular housing and adapted to rotate. A motor is provided for rotating the circular blade. The substantially circular housing is provided with a plurality of digits or guides between which hedge may be received wherein the cutting elements on the rotating circular blade may cut the hedge.
Throughout, substantially circular blade means not only a circular blade with cutting elements extending from the periphery of the circle, but various arrangements of a closed structure for the blade including an equilateral triangle and various other multi-sided figures including square, hexagon, octagon and the like. Further, although an open structure comprised of radial members interconnected in the vicinity of the periphery is presently preferred, it is understood that a solid disc shaped blade may be utilized within the spirit of the present invention. However, the presently preferred embodiment has a substantially circular peripheral configuration with cutting elements extending from the periphery thereof.
In a presently preferred embodiment, the handle projects substantially in a radial direction with respect to the circular housing with the motor for rotating the circular blade being mounted in a distal or far end of the handle, thereby providing balance between the circular housing with the cutting blade on one end and the motor at the other end. Additionally, in a presently preferred embodiment, the handle, for ergonomic reasons, is formed to slope upwardly at a small angle. However, it is understood that the invention may be practiced without such sloping.
In a presently preferred embodiment, the substantially circular cutting blade has three cutting elements mounted equally distant around the periphery of the substantially circular blade, but it is understood that more or less cutting elements may be utilized. In a presently preferred embodiment, the cutting elements are generally U-shaped. The sharp portion of the U-shaped blade is in the direction of rotation of the circumference of the blade.
In a presently preferred embodiment, the digits are shaped and arranged such that the space between the digits is such that it prevents contact of body parts with the cutting elements of the circular blade.
In a presently preferred embodiment of the invention, the substantially circular cutting blade is provided with low-friction pads mounted to the blade with the pads riding against an upper and lower portion of the circular housing. In a presently preferred embodiment, the pads are elongated and arranged to create a fan action for blowing air outwardly from the substantially circular housing as the blade rotates.
Various arrangements of the cutting blade with respect to the drive shaft may be utilized. In one embodiment, the drive shaft comes in below the cutting blade. In a presently preferred embodiment, the drive shaft would come in above the cutting blade, placing the cutting blade closer to the lower edge of the substantially circular housing. This provides the advantage of the cutting element and the cutting occurring closer to the bottom edge of the housing.
In a presently preferred embodiment, a release mechanism is provided for releasing the substantially circular blade from the motor to prevent damage should the blade be stopped when the motor is operating. In a presently preferred embodiment, the blade is driven through a clutch. The clutch may be in the form of a pair of rounded interdigitated gears or teeth held in engagement by a resilient force whereby the gears or teeth may disengage by compressing the resilient force when the blade is stopped. Other forms of release mechanisms or clutches may be used in practicing the present invention.
In a presently preferred embodiment, a latch means is provided which securely retains the upper portion and the lower portion of the housing together, along with the blade sandwiched therein, but allows for tool-less ease of disassembly for sharpening, replacement of the blade or the like.